regex101: build, test, and debug regex
Regular expression tester with syntax highlighting, explanation, cheat sheet for PHP/PCRE, Python, GO, JavaScript, Java, C#/.NET, Rust.
RegExr: Learn, Build, & Test RegEx
RegExr is an online tool to learn, build, & test Regular Expressions (RegEx / RegExp).
Regular expression - Wikipedia
A regular expression (shortened as regex or regexp), [1] sometimes referred to as a rational expression, [2][3] is a sequence of characters that specifies a …
Regex Tutorial - How to write Regular Expressions
Dec 22, 2025 · A regular expression (regex) is a sequence of characters that defines a search pattern. It is mainly used for pattern matching in strings, …
Regex Cheat Sheet
Regular Expressions Syntax Reference. Includes tables showing syntax, examples and matches.
Regular expression syntax cheat sheet - JavaScript | MDN
Mar 17, 2026 · Regular expression syntax cheat sheet This page provides an overall cheat sheet of all the capabilities of RegExp syntax by aggregating …
Python RegEx - W3Schools
A RegEx, or Regular Expression, is a sequence of characters that forms a search pattern. RegEx can be used to check if a string contains the specified …
SimpleRegex - Free Online Regex Tester & Pattern Generator
Test and generate regular expressions in real-time. Free online regex tool for developers with syntax highlighting, pre-built examples, and instant match …
Regex Tutorial - A Cheatsheet with Examples - Regextutorial.org
Regular expressions or commonly called as Regex or Regexp is technically a string (a combination of alphabets, numbers and special characters) of text …
Regular expression HOWTO — Python 3.14.5 documentation
2 days ago · Regular expression HOWTO ¶ Author: A.M. Kuchling <amk @ amk. ca> Abstract This document is an introductory tutorial to using regular …